1. Field of the Invention
The present invention relates to a printer, copier, facsimile apparatus, a multifunction machine or similar image forming apparatus. More particularly, the present invention relates to an image forming system having various finishing functions including a stapling function, a punching function, and a sorting function.
2. Description of the Background Art
It is a common practice with a printer connected to a host to print a document prepared on the host. In this case, the operator of the host usually gives little consideration to the sizes or the positions of sheets stacked on the trays of the printer. This is contrastive to the case wherein a person directly operates a copier to copy a document. Further, when a plurality of hosts share a single printer via a network, the printer is rarely near at hand for a person desiring to use the printer. The person therefore gives least consideration to the conditions of sheets stored in the printer. Moreover, there is an increasing demand for more advanced paper handling practicable by stacking various kinds of sheets on the trays and storing the characteristics of the sheets in the printer.
Today, a multifunction machine capable not only of printing out data received from a host but also copying a document is extensively used. Furthermore; finishing functions of recent years and selection thereof are extremely sophisticated. For example, the selection of an operation mode available with a finisher selectively mounted to a machine is becoming sophisticated. In addition, a plurality of different finishers are sometimes connected to a single machine.
Japanese Patent Laid-Open Publication No. 9-261415, for example, discloses an image forming apparatus capable of stapling a stack of prints at the top, bottom, right or left of the stack at one or two points or at one corner or punching the sheets. It has been customary with an image forming apparatus to identify the orientation of a text image to be copied and then execute adequate rotation to thereby staple a stack of prints in the same direction.
Assume that the operator of a printer with a finisher having a stapling function and a punching function selects, e.g., the stapling function. Then, the printer staples a sheet stack as designed by the operator and therefore sometimes staples it in an unexpected direction. Further, assume that the operator starts up an application for causing the printer to print a desired document while selecting, e.g., the stapling function and then cause it to print another document with the same application without changing the setting of a driver. Then, the finisher is apt to staple a sheet stack in an unexpected manner in accordance with the previous setting. Moreover, when the stapler staples a stack of sheets of different sizes, images on the stapled sheets would be different in direction from each other and therefore difficult to see if adequate control were not executed.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 2000-16684 and 2001-26357.
It is an object of the present invention to provide an image forming system capable of executing stapling, punching, sorting or similar finishing faithful to the operator""s intention.
It is another object of the present invention to provide an image forming system capable of adequately stapling a sheet stack matching with the sizes of sheets, printing direction, and designated stapling position.
In accordance with the present invention, an image forming system includes an image forming section for forming an image on a sheet fed thereto. A stapler included in a finisher staples a stack of sheets each carrying image formed by the image forming section thereon. A controller causes the image forming section to form an image in accordance with input image data and causes the stapler to staple the stack of sheets at a preselected point or points. When sheets of different sizes are mixed together, the controller inhibits the stapler from stapling the stack except when the short edges of a large size sheet and the long edges of a small size sheet are identical in length in a direction perpendicular to the direction of sheet feed and when all the images printed on the sheets have the same orientation when the stapled stack is spread.
Also, in accordance with the present invention, an image forming apparatus includes an image forming section for forming an image on a sheet in accordance with image data and print conditions input thereto. A sheet feed section feeds a sheet to the image forming section. The sheet feed section includes a plurality of trays each being loaded with a stack of sheets of a particular size in a short edge feed position in which the long edges of the sheets are parallel to the direction of sheet feed or a long edge feed position in which they are perpendicular to the above direction. A sheet discharge section sequentially discharges the sheets sequentially coming out of the image forming section. A stapler staples the sheets stacked thereon. A controller controls the image forming section, sheet feed section, sheet discharge section, and stapler. The controller selects any one of the trays in accordance with, among the print conditions, the stapling position of the stack and the direction of image formation on the sheets.